JPS6383907A - Thin film magnetic head of planar construction and manufacture thereof - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Background of the Invention) The present invention relates to a process for manufacturing a thin film magnetic head with a planar structure and a head obtained by this process.

Two types of thin film magnetic heads are known: those mounted at right angles to the read or write magnetic film, and those mounted parallel to the magnetic film.

For example, the head shown in FIG. 1 consists of two pole pieces P1 and P2 that define an air gap E and a coil B surrounding the pole pieces. The recording film C passes in front of the air gap E. Such a head is disclosed in, for example, Japanese Patent Abstract vol. 1.5 dated September 22, 1981. No, 150.
P-81,822.

The large magnetic gradient generated by such a head creates a strong demagnetizing field in the recording film, which makes writing difficult. Furthermore, during reading, a signal V as shown in FIG. 2 is generated. At right angles to the external angle of the pole piece, a reversal of voltage polarity occurs, which causes serious problems with the information readout process.

For these reasons, it is recommended to use a type head for horizontal mounting as shown in FIG.

Such a head is described in European patent application 85400136.9, published no. 0152326. As can be seen from FIG. 3, there is a first magnetic film 1,
There is a second magnetic film in which a coil 2 is formed and which is divided into two parts by a magnetic spacer 4 . A hard membrane 5 protects the assembly and ensures flatness of the membrane.

In FIG. 4 a known process for manufacturing horizontal heads is shown. This process is described in Japanese Patent Abstract vol. 1.5 dated January 14, 1981. No, 5. P-44,6
It is explained in 77. First magnetic film M1 on the substrate 6
is deposited, followed by insulation@7 and coil B (see FIG. 4C). After this, an insulating film 8 is deposited and two further wells P1 and P2 are etched (see FIG. 4). After this, a second magnetic film M2 is deposited, which M2 covers the two wells P1.
As a result of the formation of P2 and P2, it comes into contact with the first magnetic film (see FIG. 4C). This is followed by the formation of the air gap, the deposition of the glass layer (see FIG. 4C) and the planarization of the assembly (see FIG. 4C) in this order.

Although sufficient in certain respects, these prior art techniques and procedures have several disadvantages. In the case of the head shown in FIG. 3, the ends of the pole pieces are still exposed to the outside, so there is a risk that the read signal will be reversed. In the process illustrated in FIG. 4, the ends of the pole pieces are prevented from becoming fine or thin, but because the air gap is open to the outside and relatively wide, This air gap is gradually filled with magnetic particles, eventually magnetically shorting the head. Finally, the magnetic flux generated by the coil flows along the sub-chamber circuit, resulting in a zero magnetic flux density at the air gap. Furthermore, in the process of Figure 4, coil B is not in just one plane, but in two separate planes, one of which is above the first pole piece. Corresponding to the center, another lower plane corresponds to the two sides (only one of which is shown, for example, on the right in FIG. 4a). This side makes it possible to close the winding around the pole piece. Furthermore, it can be seen that since the magnetic pole piece M1 is not embedded in the substrate 6, the head bulges out greatly. Eventually, the part of the pole piece M2 not covered by the protective film 9 becomes very wide (as it is essentially as wide as the coil), and the head therefore becomes very fragile.

(Summary of the invention) The aim of the invention is to avoid these disadvantages.

The present invention therefore makes it possible to narrow the air gap formed by the magnetic membrane and the pole piece, so that the magnetic flux density occurs in the vicinity of the air gap and the unprotected surface becomes smaller. We propose a new manufacturing process.

Additionally, the process of the present invention allows structures that are embedded or nested in the substrate, so that no bulges occur. An additional advantage is that the process of the present invention, unlike prior art processes, does not require a sanding finish.

The process of the present invention includes conventional thin film deposition and etching operations associated with integrated circuit technology, as well as field deposition operations for various magnetic films.

The invention further relates to a magnetic head obtained by the process of the invention.

(Example) FIG. 5 shows the main steps of the process of the invention.

The present invention consists of the following operations.

A first insulating film 12 (eg, silicon oxide) is formed on an insulating substrate, plate 10, of silicon, for example (see FIG. 5g). The insulating film 12 and the substrate 10 are patterned, so that a first recess 13 is formed (see FIG. 5). A first conductive layer 14 is deposited thereon and further selectively etched so that it remains only at the bottom of the first recess 13 (see FIG. 5). By a first electrolysis using the conductive film 14 as an electrode, a first magnetic film 16 is deposited flush with the first insulating film 12 and fills the recess 13 (see FIG. 5C). In this way, the magnetic film is embedded or fitted into the substrate.

A second insulating film 18 is deposited on the structure thus formed (see FIG. 5C). An electric coil 20 is formed in this second insulating film 18 (see FIG. 5C). Such an operation is described in the aforementioned European patent application (Figures 3 and 4 thereof). This coil has a 20° side
(only one of the two shown) is closed, but its sides are flush with the central portion 20. On both sides of the coil 20, the second insulating film 18 is etched.
Two openings 21 and 22 are formed so that they reach the first magnetic film 16 (see FIG. 5C).

By performing a second electrolysis using the first conductive film 14 as an electrode, these two openings are filled to form magnetic contact pads 23 and 24, respectively. It has good magnetic conductivity with the first magnetic film 16 and is on the same plane as the second insulating film 18 (see FIG. 5g).

On this object, for example 5i02. A third insulation@26, such as Al2O3, polyimide resin, etc., is deposited (see fifth diagram). Second. The third recess 27 and z8 are.

This third insulating film 26 overlying the magnetic contact pads 23 and 24 is etched so that these second . A central insulating island 32 will remain between the third recesses (see Figure 5). A second conductive film 33 is deposited on this object and further selectively etched, so that this film remains only at the bottoms of the second and third recesses 27, 28 (fifth (see diagram).

By performing the third electrolysis using the second conductive film 33 as an electrode, the second conductive film 33 is used as an electrode. The third recess is filled with a second magnetic film, resulting in two mutually separated portions 30. :11
are formed on both sides of the central insulating island 32, and the second magnetic film is coplanar with the third insulating film 26 (see FIG. 5). A fourth hard protective insulating film 34 is deposited on this object (see FIG. 5j). A thin magnetic spacer is formed in the corresponding fourth recess 36 at the center of the central insulation island. Such a spacer is formed by depositing an insulator 3B and etching it in steps, depositing a magnetic film 40 (see FIG. 5), as described in the aforementioned European patent application. Additionally, by etching the horizontal portions to maintain vertical walls 42 (see FIG.
Reference) can be obtained. A third conductive film 43 is deposited on this object and further selectively etched.
It remains only at the bottoms of the fourth recesses 36 on both sides of the spacer 42 (see FIG. 5, 1).

By performing a fourth electrolysis using the third conductive film 43 as an electrode, the fourth recess 36 is separated into two portions 46 and 48 located on both sides of the magnetic spacer 42. This third magnetic film is on the same surface as the hard protective film 34 (see FIG. 5m). Therefore, unlike the prior art, there is no need to polish this part.

In this process, conductive films 14.33 and 43 may be copper, chromium or tungsten, for example. Magnetic films 16, 23, 24, 30. :II, 46 and 48 are
In order to obtain high magnetic permeability, the Fe:Ni ratio is, for example, 80:
It may be 20. The thickness of the magnetic film 16 may be from 1 micron to 5 microns. The thickness of the vertical wall 42 is 0.05
A micron to 1 micron is sufficient. The thickness X of the central contact pad 32 is between 1 micron and 5 microns (FIG. 5-1).
reference). The thickness of the hard membrane 34 may be between 1 micron and 5 microns. The etching width Y is between 5 microns and 15 microns (see Figure 5j).

FIG. 6 shows a cross-sectional view of a complete head whose magnetic field lines allow the magnetic flux density in the vicinity of the air gap to be discerned. The pressure U in sections 46 and 48 is approximately 10
microns, but the thickness of coil 18 is between 120 and 200 microns. This makes the unprotected portion of the pole piece extremely narrow.

[Brief explanation of the drawing]

FIG. 1 shows a known magnetic head mounted vertically, as mentioned above. As already mentioned, FIG. 2 shows the waveform structure of the signal generated by the head shown in FIG. FIG. 3 shows a known magnetic head mounted horizontally as already mentioned. FIG. 4 shows, as already mentioned, a known process for manufacturing horizontal heads. FIG. 5 shows the 13 steps (a) of the manufacturing process according to the invention.
to m). FIG. 6 shows the magnetic head actually obtained.

Claims (2)

[Claims] (1) forming a first insulating film on an insulating substrate, etching this insulating film and the insulating substrate to form a first recess,
A first conductive film is deposited thereon, selectively etched so that it remains only at the bottom of this first recess, and a first electrolysis is performed using this conductive film as an electrode to form a first magnetic film. depositing a second insulating film over this entity, thereby filling the recess so that the first magnetic film is coplanar with the first insulating film, and depositing a second insulating film in the second insulating film. A second insulating film is formed, forming an electrical coil, etching this second insulating film on both sides of the coil, thereby creating two openings that reach the first magnetic film, and using the first conductive film as an electrode. electrolysis to fill the two openings and form two magnetic contact pads that have good magnetic conductivity with the first magnetic film and are also identical to the second insulating film. A third insulating film is deposited on the object, and the third insulating film on the magnetic contact pad is etched to form the second and third insulating films.
At the same time, a central insulating island is left between the second and third recesses, and a second conductive film is deposited on this object and selectively etched to form the second and third recesses. A third electrolysis is performed using this second conductive film as an electrode, leaving only the bottom of the second and third conductive films.
is filled by a second magnetic film, thereby forming two mutually separated portions on either side of the central insulation island, the insulation film being coplanar with the third insulation film and on top of the object. A fourth hard protective insulating film is deposited and etched to form a fourth recess over the central insulating island to reach the second magnetic film, and a thin magnetic spacer is placed in the fourth recess. A third conductive film is formed at the center of the central insulating island, deposited on the object and selectively etched so that it remains only at the bottom of the fourth recess on each side of the spacer. Perform a fourth electrolysis using the conductive film as an electrode
of a planar structure, characterized in that the recess is filled with a third magnetic film separated in two parts on both sides of the magnetic spacer, the third magnetic film being on the same surface as the hard protective film. A method for manufacturing a thin film magnetic head. (2) An insulating substrate, a first magnetic film embedded in the same plane within this substrate, two magnetic contact pads present at both ends of this first magnetic film, and two magnetic contact pads located in the insulating film. An electrical coil wrapped around these two contact pads,
an insulating island located over the center of the coil, a second magnetic film separated into two parts by an insulator contact pad, and a second magnetic film separated into two parts on these two parts. consisting of a separated third magnetic film;
A thin film magnetic head having a planar structure, wherein the two parts are separated by a magnetic spacer, and the third film is embedded in a hard protective insulating film.